ES2376426T3 - SUPPLY SYSTEM BASED ON A DATE THAT HAS SECTIONS OF DIFFERENT POROSITIES. - Google Patents

Abstract

A dispensing device for a vaporizable material is disclosed which has a container (1) for holding a vaporizable liquid, the container including an opening therein; and a porous wick having a first section (3a) comprised of a material with a predetermined pore size and a second section (3b) comprised of a material with a predetermined pore size that is greater than that of the first section, positioned so that a lower region of the wick will be in contact with the liquid to be held by the container and an upper region of the wick is exposed to the ambient air to dispense the vaporizable liquid. The opening in the container is substantially sealed by the wick, and the second section of the wick surrounds the portion of the wick that is exposed to the ambient air. Also disclosed is a method of dispensing a vaporizable material from a container. The method comprises positioning a porous wick in the container with a lower region in contact with the liquid in the container and an upper region extending from the container; activating the release of vaporizable material from the wick (3) to the ambient air; and deactivating the release of vaporizable material from the wick (3) to the ambient air; wherein the wick (3) has a first and a second section (3a, 3b) of different pore sizes, the pore size in the first section (3a) being smaller than the pore size in the second section (3b), such that during deactivation, due to the higher equilibrium rise within the first section of the wick than in the second section, the first section becomes saturated whereas the second section does not, and during activation, due to a lower rate of wicking in the first section than in the second section causes produces an initial "spike" effect in the emission from the wick as initially material is emitting from both first and second sections (3a, 3b) until the first section (3a) becomes depleted.

Description

Supply system based on a wick that has sections of different porosities.

Field of the Invention The present invention relates to a wick-based delivery system according to the preamble of claims 1 and 8 for transporting liquids, such as fragrances or insecticides, from a container to a surface exposed to ambient air.

2. Description of the related art Devices that release vapors into ambient air are known in the art. In general, the purpose of these devices is to deodorize or disinfect ambient air, or distribute toxins in the air to kill or repel unwanted pests, such as mosquitoes.

To achieve the goal of dispensing vapors in the air, a variety of methods have been employed. For example, aerosol containers have been used to eject vapors into the air after triggering by the user. Other methods, however, have used the evaporative properties of liquids, or other vaporizable materials, to cause vapors with desired properties to be distributed in ambient air. One such evaporative method uses a wick to deliver a vaporizable liquid from a reservoir to a surface exposed to ambient air. As the liquid reaches the exposed surface, the liquid is vaporized and dispersed in the ambient air. The exposed surface may be either the surface of the wick or the surface of another body in fluid communication with the wick.

In some applications, it is desired that the release rate of the vaporizable liquid be higher when the device is activated for the first time. This initial impulse is particularly desired when the purpose of the device is to release insecticides or insect repellents into the ambient air. In the case of insect repellents, the benefit of the initial impulse effect is that it causes the vaporizable liquid (in particular, the active ingredient of the vaporizable liquid) to spread rapidly in the air in an amount sufficient to decrease the number of insects in the surrounding area Once the optimum level of active ingredient has been released by the initial pulse and the ambient air of the operating area is sufficiently saturated, however, it is preferable that the release rate of the vaporizable liquid decreases. This decrease in the release rate is preferred because the optimum saturation level of the ambient air has already been achieved, and the release rate of the vaporizable liquid after the initial period need only be sufficient to maintain that optimum level.

Therefore, when an insect control device is activated for the first time, it is preferred that the device initially releases a relatively high amount of the vaporizable liquid into the ambient air, and then, after the initial pulse, the release rate of the device should Stay at a lower level.

An example of a wick-based controlled release device is described in U.S. Patent No. 4,915,301. This patent describes a bottle for dispensing a vapor phase liquid. More specifically, the bottle contains a liquid, and that liquid is absorbed by a wick and transported to a porous body. The liquid then spreads through the porous body and reaches a microporous membrane that allows the liquid to discharge into the atmosphere. The membrane serves to allow the emission of liquid vapors, while preventing the passage of the liquid itself. Therefore, the exposed surface of this device consists exclusively of a microporous membrane. While this membrane helps prevent liquid spillage through the wick, it cannot provide an initial impulse effect followed by a stable, lower release rate.

U.S. Patent No. 6,109,539 describes an inverted aromatic substance dispenser that may be composed of porous shutters with different porosities. However, this dispenser also has a material of only one pore size exposed to ambient air and, therefore, this dispenser cannot provide an initial pulse effect followed by a stable, lower release rate. Another wick device is described in U.S. Patent No. 2,277,377. This patent describes a device comprising a core made of bentonite, a clay-like substance surrounded by a cotton sheath. The device is inserted into a reservoir after which the cotton lifts the liquid from the reservoir. Bentonite absorbs the liquid, expanding, since it does not until its pores close, suffocating. As the bentonite subsequently dries, it gradually releases the absorbed liquid. This wick structure is unsatisfactory for a household product because the wick is soft in the wet state. In addition, a seal with no container would not be possible due to the change in size as the bentonite absorbs the liquid.

Document FR 2 772 275 shows a flavored bottle with a wick that extends into the liquid and a porous sphere at the top of the lid and connected to the wick. This causes the liquid to spread to the wick and vaporize from the porous sphere at the top of the bottle.

US 4,419,326 shows a bottle of a vaporizable liquid with two wicks that pass through holes in an impermeable cap and that are connected to a rigid porous cap of a polyethylene material. The lid has an open cell hemispheric surface from which the liquid vaporizes. As the liquid vaporizes, it is replenished by the wick. The wick consists of a mass of continuous filament nylon fiber, the porosity of the wick or hemispherical cap is not described.

SUMMARY OF THE INVENTION The invention is defined in independent claims 1 and 8 below.

A better understanding of these and other features and advantages of the invention can be obtained by reference to the drawings and the accompanying description, where preferred embodiments of the invention are illustrated and described.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows an exploded view of a supply system based on a wick according to

a preferred embodiment of the present invention.

Figure 2A shows a top view of a wick according to another preferred embodiment of the

present invention

Figure 2B shows a side view of the wick shown in Figure 2A.

Figure 3A shows a top view of a wick according to another preferred embodiment of the

present invention

Figure 3B is a sectional view taken along the dividing line A-A in Figure 3A.

Figure 4A shows a top view of a wick according to another preferred embodiment of the

present invention

Figure 4B is a sectional view taken along the dividing line B-B in Figure 4A.

Figure 5 shows a view of a supply system based on a wick in accordance with the present

invention, which is being used together with an optional electric plug-in heater.

In all figures, similar or corresponding reference numbers have been used for similar or corresponding parts.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supply system based on a wick for transporting a liquid from a reservoir to a surface exposed to ambient air. In its simplest form, the invention comprises a device that includes a container for holding a liquid, and a two-section wick for transporting the liquid from the container to an upper surface of the wick.

The container can be formed in a variety of ways. In Figure 1, for example, the container is a bottle 1 in a conventional manner. A wick 3 has a shape such as to fit a neck 5 of the bottle 1. The wick 3 is long enough so that its lower surfaces come into contact with the liquid in the bottle 1 and its upper surfaces are exposed to ambient air . (The level of the liquid is not shown in the bottle 1.) It is preferable to use a neck closure 2, like the one shown in Figure 1, to hold the wick 3 in place and prevent spillage around the neck 5 of the bottle 1. The fit between neck closure 2 and bottle 1 is firm enough to prevent spillage of liquid from bottle 1. Also, the fit between neck closure 2 and wick 3 is firm enough to prevent spillage of liquid from the bottle 1.

The neck closure 2 or the neck 5 of the bottle 1 can be formed with a small hole (for example, a breathing hole) to help combat the effects of a vacuum that can be formed in the head space of the bottle

1. The wick 3 transports the liquid to the surface of the wick 3 by a principle called capillary action. In particular, the wick material contains numerous pores, and these pores act as capillaries that cause the liquid to be drawn into them. As the liquid is drawn from the bottle and transported to the porous wick 3, a vacuum is created in the head space of the bottle 1. The formation of a vacuum in the head space of the bottle 1 decreases the rate at which the Liquid is transported by the wick from the tank to the surface. Of course, this decrease in the rate of transport through the wick translates directly into a reduction in the rate of release of the liquid into the ambient air. Therefore, in order to combat the formation of the vacuum in the head space, it is often preferable to form a breathing hole in the vicinity of the head space of the bottle 1.

In addition, the neck 5 of the bottle 1 can have a shape such that a cover 4 can be attached on the wick 3 and the neck closure 2. For example, the outer neck 5 of the bottle 1 can be threaded so that it you can thread a cover 4 on top of the bottle 1 when the device is not in use.

The bottle 1 and neck closure 2 may be made of any suitable material that is leakproof. Of course, the size of the opening in the bottle 1 and the size of the neck closure 2 depend on each other, and on the size of the wick 3 to be used with the device.

The wick 3 can be made of a variety of materials. It is preferable that the wick 3 is rigid enough to provide a minimum contact area with the surface with which the wick 3 comes into contact. It has been found that polymeric wicks, for example, are effective for these purposes. In particular, it has been found that ultra high molecular weight high density polyethylene (HDPE) wicks are suitable. Such wicks in general are composed of particulate HDPE mixtures, and the mixtures are created to meet the target pore characteristics of the wick 3.

Preferably, the polymer solubility parameter is significantly different from that of any of the components contained in the liquid. This prevents the wick 3 from expanding, or other changes, which can lead to a change in the pore size and the porosity of the wick 3. If the pore size or porosity of the wick 3 is altered, the index of Release of the vaporizable liquid in the ambient air would also be affected.

As described above, it is often desired that the device exhibits an initial pulse in the vaporizable liquid release rate when the device is first activated. More specifically, when an insect repellent device is activated, an initial boost in the release rate of the active ingredient (e.g. insecticide) is desired in order to rapidly disperse in the air a sufficient amount of the active ingredient to effectively reduce the amount of insects in the surrounding area. Once an optimal level of active ingredient is present in the ambient air of the operating area, however, the release rate of the active ingredient should decrease to an amount sufficient to maintain that optimum level. By having two sections of variable pore size exposed to ambient air simultaneously, it is possible to achieve an initial impulse effect.

In particular, the initial impulse effect is achieved by having a wick 3 comprised of at least two sections. A first section 3a is made of a material that has a particular pore size, while the second section 3b is made of a material that has a pore size that is larger than that of the material of the first section. Both sections of the wick are exposed to ambient air.

In Figure 1, the cylindrical shape of the large pore section 3b is also narrowed in its lower portion. The pore size of the lower portion of the large pore section 3b, however, does not change with this change in diameter. It should be noted that this change in form is not required to achieve the initial momentum effect. instead, this variation in shape can be useful, since it increases the amount of surface area exposed to ambient air and helps to form a firmer seal in the neck area 5 of bottle 1, thus helping to avoid spills or leaks of the liquid in the bottle 1.

In general terms, the increase in equilibrium within a wick increases as the pore size decreases, while the rate of transport through the wick decreases as the pore size decreases. Therefore, a wick 3 with a small pore size will transport a liquid more slowly, but the capillary action will be greater. Since the increase in equilibrium within a wick 3 increases as the pore size decreases, the small pore section 3a will saturate with the liquid, and the large pore section 3b will not, when the device is not activated. .

When the device is activated, the liquid is released from all exposed surfaces of the wick 3, which includes a surface of the small pore section 3a and a surface of the large pore section 3b. However, when the liquid in the small pore section 3a is depleted, the small size of the pores in that section delays the transport of additional liquid through the wick to the small pore section 3a. Consequently, as soon as the device is activated, the section of small pores 3a no longer contributes to the release of the liquid into the environment.

When the device is deactivated, the strong capillary action of the small pore size section 3a causes the area of the small pore section 3a to become saturated with the liquid again. In this way, the device is able to provide the initial impulse effect as long as there is enough liquid remaining in the system and enough time for the small pore section 3a to replenish itself between the cycles of use.

Therefore, when an insect control device of the present invention is activated for the first time, the liquid (active ingredient) is initially released into the ambient air from both exposed wick sections 3a and 3b, and then, after it is depletes the small pore section 3a, the release rate of the device is limited to the index at which the larger pore section 3b works to disperse the vaporized liquid into the ambient air.

[0035] Of course, the initial pulse effect described above can be obtained with wicks 3 in many different shapes and configurations. Figure 1, for example, shows a wick 3 having a section of small pores 3a of cylindrical shape stacked on a section of larger pores 3b, also of cylindrical shape. Figures 2A, 2B, 3A and 3B show other possible configurations, which are discussed in more detail below.

Whenever the exposed surface of the wick 3 contains a section with a sufficiently small pore size and a section with a sufficiently large pore size, the small pore size section will deplete itself and cause the initial impulse effect above. described

The preferred pore size of the small pore size section 3a and the large pore size section 3b will vary depending on the composition of the liquid to be dispersed in the air. However, we have found that it is preferable that the ratio of the large pore size to the small pore size is above about two, and more preferably above about five, and even more preferably above about ten, for any given viscosity. In other words, if the large pore size is around ten micrometers, the small pore size is more preferably below a micrometer. If the large pore size is around one hundred micrometers, the small pore size is most preferably below ten micrometers. It should be noted that any difference in pore size will produce an initial impulse effect. In the case of a smaller relationship, however, the momentum effect will also be less and, consequently, less effective.

The average pore size of the wick 3 can be determined by any standard test to determine the porosity and pore size distribution. For example, mercury porosimetry is a method that provides information about porosity and pore size distribution for rigid wicks. It is based on the measurement of differential increases in the amount of mercury introduced into the wick as a function to increase the applied pressure.

We also contemplate that there may be multiple sections of small pore size 3a exposed to ambient air. An example of a wick 3 having multiple sections of small pore size 3a is shown in Figures 2A and 2B. Indeed, it may be preferable to use several sections of small pore size 3a in order to achieve a more uniform initial impulse effect and / or minimize leakage from the wick 3, as described above. Furthermore, it is possible that the small pore section 3a can be arranged so that it extends into the bottle 1 and is itself in contact with the liquid in the bottle 1.

Figures s 3A and 3B show even another possible wick configuration to achieve a pulse effect. In this example, the small pore size section 3a is concentrically disposed within the larger pore size section 3b.

Another advantage of using a wick 3 that has a small pore size section is that the probability of the liquid spilling or seeping through the wick itself can be reduced. In particular, the liquid is less likely to escape from the small pore section 3a and, therefore, it is possible to design the wick so that the small pore section 3a is arranged in the area from which the liquid is more likely It spills. As previously indicated, it is not necessary that the small pore section 3a be positioned as indicated in Figure 1. Instead, the small pore section 3a could be arranged, for example, on the side to which it is most likely that the device is tilted (either in use by the consumer or in manufacturing or shipping by the producer). Consequently, the section of small pores 3a could be arranged where it is most likely to help in the prevention of leaks or spills of the liquid through the wick 3.

For example, as shown in Figures 4A and 4B, it is possible to provide a wick 3 with an outer layer composed of a material with larger pore sizes. In Figures 4A and 4B, the outer section of large pores 3b completely surrounds the exposed portion of the wick 3. The smallest pore size section 3a extends towards the bottle 1 and is in contact with the liquid. Thus, the smaller pores of the inner portion 3a of the wick 3 prevent spills, while the larger pores of the outer portion 3b provide a maximum release rate of the vaporizable liquid from the surface of the wick 3 exposed to the air ambient. It should be noted, however, that the large pore section 3b does not need to completely surround the upper region of the small pore section 3a as shown in Figures 4A and 4B in order to provide the benefits of our invention.

The present wick-based delivery system can also be combined with an electric heater to facilitate the release of the vaporizable material into the ambient air. In fact, when we talk about activation (and deactivation), in general what we mean is that the heater, or other similar mechanism, turns on and off. Of course, the device can operate without said auxiliary, and the activation and deactivation periods can be achieved simply by exposing or restricting the exposure of the wick to ambient air, such as by removing or adding a cover on the wick. Figure 3 shows an example of the type of electric heater 7 that can be used for this purpose. In addition, U.S. Patent No. 5,647,053 describes said electric plug-in heater and is incorporated herein by reference.

Other means for facilitating the use of the delivery system based on a wick of the present invention are also contemplated. For example, the invention can also be combined with a battery fan. While not required, it is preferable that the wick-based delivery system of the invention be combined with the electric plug-in heater or the fan in a removable mode. For example, the wick-based delivery system of the invention can be constructed so that the bottle 1 can be combined with an electric plug-in heater 7, for example, in a way that is quickly positioned as indicated in Figure 3.

5 While particular embodiments of the present invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention, as defined in the appended claims.

INDUSTRIAL APPLICABILITY

The present invention provides a device useful as a means of transporting a liquid from a reservoir to a surface exposed to ambient air. We contemplate that this device can preferably be used, for example, to dispense fragrances, insecticides and any other vaporizable material in the ambient air to cool or deodorize the air, or to exterminate airborne pests.

Claims (14)

one.

A device comprising:

a container (1) containing a liquid for vaporization; and a porous wick (3) having a first section (3a) comprised of a material with a predetermined pore size, and a second section (3b) comprised of a material with a predetermined pore size that is larger than that of the material of the first section (3a) positioned such that a lower region of the wick will be in contact with the liquid that will be contained by the container (1) and an upper region of the wick will be exposed to ambient air, where at least a portion of the first section (3a) and at least a portion of the second section (3b) are exposed to ambient air, characterized in that both sections (3a, 3b) of said wick (3) are composed of a polymeric material with a solubility parameter significantly different from that of any component contained in the liquid, so that the sections (3a, 3b) of the wick (3) do not change in pore size and porosity when s and expose said liquid.

2.

The device according to claim 1, further comprising a plurality of at least one of the first section (3a) and the second section (3b).

3.

The device according to claim 1, wherein the first section (3a) is formed in the upper part of the second section (3b).

Four.

The device according to claim 3, wherein each of the first section (3a) and the second section (3b) is cylindrical in shape.

5.

The device according to claim 1, wherein the first section (3a) is concentrically formed within the second section (3b).

6.

The device according to any preceding claim, wherein the container has an opening (5) in its upper part; and the wick (3) extends through the opening (5) in the container (1) such that a lower region of the wick (3) will be in contact with the liquid to be contained by the container ( 1), and an upper region of the wick (3) will be exposed to ambient air, where the opening (5) in the container (1) is sealed by the wick (3).

7.

The device according to any preceding claim, which includes a liquid in the container (1).

8.

A device comprising:

a container (1) containing a liquid, where the container there includes an opening (5); and a porous wick (3) having a first section (3a) comprised of a material with a predetermined pore size, and a second section (3b) comprised of a material with a predetermined pore size that is larger than that of the first section (3a), positioned with a lower region of the wick in contact with the liquid contained by the container (1), and an upper region of the wick exposed to ambient air, where the opening (5) in the container (1 ) is sealed by the wick (3) and only the second section (3b) of the wick (3) is exposed to ambient air; characterized in that both sections (3a, 3b) of said wick (3) are composed of a polymeric material with a solubility parameter significantly different from that of any component contained in the liquid, such that said sections (3a, 3b) of The wick (3) does not change in pore size and porosity when exposed to said liquid.

9.

The device according to claims 6 or 8, further comprising a neck closure (2) having a hole, wherein the neck closure (2) fits snugly to the opening (5) of the container (1), and the wick (3) fits tightly to the neck closure hole (2), such that the opening (5) of the container (1) is sealed by the neck closure (2) and the wick (3).

10.

 The device according to any preceding claim, wherein the ratio of the pore size of the second section (3b) to that of the first section (3a) is greater than about two.

eleven.

 The device according to any preceding claim, wherein the ratio of the pore size of the second section (3b) to that of the first section (3a) is greater than about five.

12.

 The device according to any preceding claim, wherein the ratio of the pore size of the second section (3b) to that of the first section (3a) is greater than about ten.

13.

 The device according to any preceding claim, further comprising a heater (7) for heating the entrained liquid through the wick.

14.

 The device according to any preceding claim, wherein the heater (7) is an electric plug-in heater.